Recently, automobiles equipped with ECUs (Electronic Control Units) have been designed to achieve control functions for engines with ECUs. Herein, ECUs are one type of computer which achieves desired functions according to computer programs. Normally, it is necessary to update computer programs for ECUs installed in already-used automobiles on inspection or periodic inspection of automobiles in conventional automobile repair shops.
Conventionally, an operator involved in updating computer programs for ECUs should connect a diagnosis terminal, exclusively used for automobiles, to a diagnostic port of an automobile, which is called an OBD (On-Board Diagnostics) port, and therefore the operator can install updated programs and change settings of data with the diagnosis terminal. In this connection, for example, Non-Patent Literatures 1, 2 disclose technologies concerning security for ECUs.